You need to synchronize the Tumult Hype Animation with your video timeline
You can integrate the entire movie into your timeline. Using the Tumult Hype Animation tool you can create a new animation that matches your video timeline, but Hype is incapable to modify your existing video.
You can connect to data using something like Hype Data Magic and set arbitrary information in it; like a headline. You can also then integrate Hype Data Magic with other APIs that you want (weather, stocks etc.) and use the information in your timelines.
HTML5 and video are two different technologies. One uses a DOM to render and behaves more like a layout. Video is pixel-based and therefor you cannot truly mix them. You can only overlay the one over the other.
The end result of these snapshots of overlapping layers (HTML5, Video) are then stiched and saved as a pure native video (without sound).